gophers
-------
Sean Caron scaron@umich.edu

### Installation

1. acme gophers.c

2. specify the FQDN of the host on which the server is running in the HOST_NAME #define.

3. mk

4. cp ./gophers /usr/you/bin/yourarch

### Usage

```
./gophers [port] [gopher root directory] [logfile]
```

### Notes

All command line parameters are mandatory.

The gopher server serves up documents from the gopher root directory. The theory of operation is as follows.

```
repeat forever {
    get a request from the client

    catenate the request path with the root directory to get a real filesystem path

    stat this file to see if it is a file or directory.

    if (file) {
        spit file out to client
    }

    if (directory) {
        look for .gopher file

        if (exists) {
            assume it is in 'gopher markup language' and spit it directly to the client
        }

        else {
            generate a basic directory listing in 'gopher markup language' and send it to the client
        }
    }
}
```

### Markup language and .gopher files

What I call gopher markup language is really just lines of text formatted in a way that is RFC 1436 compliant. That is, lines of the text that the client will interpret as valid gopher selectors. They must look like this:

```
[type][selector]\t[path]\t[server name]\t[port]\n
```

Where \t=tab and \n=hit RETURN.

The [type] field is a one-character code that describes the filetype. It should be one of the following:

```
0 = plaintext
1 = directory
2 = cso search query
3 = error message
4 = binhex archive
5 = binary archive
6 = uuencoded
7 = search engine query
8 = telnet link
9 = binary file
d = pdf file
g = gif image file
h = html file
i = informational file (just displayed as text)
l = image file (e.g. jpg)
s = audio file
```

Some of these appear to be somewhat de facto additions to the original standard and might not be supported by all gopher browsers.

The other fields are defined as follows:

```
[selector] is the text of the link that is visible to the user

[path] is relative to the gopher root, make sure you begin it with a leading slash.

[server name] is the fqdn of the gopher server

[port] is the port number on which the gopher server is running.
```

If you just type a plain text line into a .gopher file the server will automatically make an i-line out of it. By plain text line, I mean a line that does not contain three tabs and have a first character equal to one of the file type codes above.

Note that gophers doesn't support the h-line URL:http://blah redirect, just file type information only.

If you are hand-coding an i-line it is customary to have a null path, host as error.host and port 1.

After typing the last line in your .gopher file, hit return, so that the file ends with a blank new line.